Porous organic polymers derived from norbornenes based on methyl-substituted anthracene

Abstract

A set of new metathesis and vinyl-addition polymers bearing different bulky framed 9,10-dihydroanthracene moieties in side chains has been prepared and studied as promising porous organic materials. The desired monomers have been readily synthesized in good yields via Diels-Alder reaction between 2,5-norbornadiene and methyl derivatives of anthracene. The ring-opening metathesis polymerization of these monomers in the presence of the 1st generation Grubbs catalyst afforded soluble high-molecular-weight products (M_w > 9 × 10⁵). Vinyl-addition polymerization over Pd-system led to saturated polymers with rigid backbones. As a result, five new polynorbornenes with regularly changed structure have been synthesized. The polymers are glassy, thermally stable, and amorphous. The investigation into their N₂, CH₄ and CO₂ sorption properties showed that the addition of methyl groups is an efficient approach to increase micro- and mesoporosity and CO₂ solubility coefficients of such polymers. The polymers with methylated 9,10-dihydroanthracene moieties exhibited large specific surface areas (up to 740 m²/g), volume of micropores up to 0.17 cm³/g and infinite dilution solubility coefficients up to 2.2 mmol g⁻¹ atm⁻¹.